1. Field of the Invention
The present invention relates to a valve switch, and in particular to a three-stage valve switch structure, that is capable of controlling the forward rotation, reverse rotation and pulling action in an existing manual machine tool.
2. The Prior Arts
In general, a blind-rivet-riveter is utilized in a manual machine tools for assembling plate members, such as the connection and fastening of the plate members, and that is achieved through putting a rivet through two plate members, and putting in a rivet mandrel for pulling rivet and for biting by making use of a rivet-setting device having jaw bits in a head portion of a blind-rivet-riveter, such that when user presses down on a handle, a rivet-setting device will be actuated to retract backward, so that a riveting mandrel will move backward to cause deformation wrinkles of a tube member of a rivet, hereby realizing connection and fastening of plate members. Usually, a blind-rivet-riveter is also referred to as a rivet-pulling-riveter, that is a kind of manual machine tool used exclusively for fastening and assembly of plate members. A rivet-nut-riveter is another kind of manual machine tool used frequently in industry and upholstery, that is also used extensively in rivet-fastening and assembly of avionic products, computers, communication products, vehicles, machineries, and etc, and various sheet members and pipe systems. By way of example, upon utilizing rivet-nut-riveter in fastening and assembly of two plate members, a rivet nut is put through between two plate members, such that a pull rod of rivet-nut-riveter having threaded section is screwed to a rivet nut. Therefore, when a user pressed down on a handle, the pull rod will be actuated to retract backward, so that a riveting mandrel will move backward to cause deformation wrinkles of a grip section on both ends of a rivet nut, hereby achieving connection and fastening of plate members. As such, in this assembly method, a pull rod is actuated to retract backward in realizing connection and fastening of plate members.
However, in proceeding with a nut riveting operation, it is usually realized through the three-stage actions of forward rotation, pulling, and reverse rotation, so as to cause deformation wrinkles of threaded sections on both ends of a rivet nut, hereby successfully retrieving the rivet nut. However, in the design of existing rivet-nut-riveter having single valve or double valves, usually the retraction of rivet nut is not complete, so that user will spend much time in taking out rivet nuts from an oil piston. As such, in case that design improvements can be made to valve switch of manual machine tool, wherein an auxiliary switch is utilized, such that when the retraction of a rivet nut reverse rotation is not complete, a pneumatic device can be actuated in reversely rotating its blades and then retracting a rivet nut completely by pressing down an auxiliary switch, hereby achieving convenience and much economic benefits.
In view of the problems and shortcomings of the prior art, the present invention provides a three-stage valve switch structure, so as to solve the afore-mentioned problems of the prior art.